Rubber-Like Polymer, Method for Producing Rubber-Like Polymer, Rubber Composition, and Tire Tread

Abstract

A rubber-like polymer,wherein a sum of a content C1 of a structure represented by the following formula (1) and a content C2 of a structure represented by the following formula (2) is 40 mol % or more and 60 mol % or less;a content C3 of a structure represented by the following formula (3) is 15 mol % or more and 60 mol % or less;a content C4 of a structure represented by the following formula (4) is 2 mol % or more and 25 mol % or less;a content S of an aromatic vinyl monomer unit is 4 mol % or more and 18 mol % or less;a weight average molecular weight measured by gel permeation chromatography (GPC) is 300,000 or more; anda modification ratio measured by column adsorption GPC is 60% by mass or more:

1 . A rubber-like polymer,
 wherein a sum of a content C1 of a structure represented by the following formula (1) and a content C2 of a structure represented by the following formula (2) is 40 mol % or more and 60 mol % or less;   a content C3 of a structure represented by the following formula (3) is 15 mol % or more and 60 mol % or less;   a content C4 of a structure represented by the following formula (4) is 2 mol % or more and 25 mol % or less;   a content S of an aromatic vinyl monomer unit is 4 mol % or more and 18 mol % or less;   a weight average molecular weight measured by gel permeation chromatography (GPC) is 300,000 or more; and   a modification ratio measured by column adsorption GPC is 60% by mass or more:   
       
         
           
           
               
               
           
         
       
     
     
         2 . The rubber-like polymer according to  claim 1 ,
 wherein the sum of the content C1 of the structure represented by the formula (1) and the content C2 of the structure represented by the formula (2) is 40 mol % or more and 60 mol % or less,   the content C3 of the structure represented by the formula (3) is 15 mol % or more and 60 mol % or less,   the content C4 of the structure represented by the formula (4) is 5 mol % or more and 25 mol % or less,   the content S of the aromatic vinyl monomer unit is 4 mol % or more and 15 mol % or less,   the weight average molecular weight measured by gel permeation chromatography (GPC) is 300,000 or more, and   the modification ratio measured by column adsorption GPC is 60% by mass or more.   
     
     
         3 . The rubber-like polymer according to  claim 1 , wherein a ratio between a weight average molecular weight Mw and a Mooney viscosity ML measured at 100° C., Mw/(ML×10,000), is 0.68 or more and 0.85 or less. 
     
     
         4 . The rubber-like polymer according to  claim 1 ,
 wherein a nitrogen content is 10 ppm or more and 80 ppm or less.   
     
     
         5 . The rubber-like polymer according to  claim 1 ,
 wherein the nitrogen content is 35 ppm or more and 80 ppm or less.   
     
     
         6 . The rubber-like polymer according to  claim 1 ,
 wherein a silicon content is 50 ppm or more and 200 ppm or less.   
     
     
         7 . A method for producing the rubber-like polymer according to  claim 1 , comprising:
 a step of copolymerizing a conjugated diene-based compound and an aromatic vinyl compound, and hydrogenating the resultant copolymer such that a hydrogenation rate of 90% or less is achieved.   
     
     
         8 . A rubber composition, comprising:
 100 parts by mass of a rubber component including the rubber-like polymer according to  claim 1 ; and   0.1 parts by mass or more and 20 parts by mass or less of a crosslinking agent.   
     
     
         9 . A rubber composition, comprising:
 100 parts by mass of a rubber component including the rubber-like polymer according to  claim 1 ; and   0.1 parts by mass or more and 30 parts by mass or less of a silane coupling agent.   
     
     
         10 . A rubber composition, comprising:
 100 parts by mass of a rubber component including the rubber-like polymer according to  claim 1 ; and   1 part by mass or more and 60 parts by mass or less of a softener.   
     
     
         11 . A rubber composition, comprising:
 100 parts by mass of a rubber component including the rubber-like polymer according to  claim 1 ; and   30 parts by mass or more and 100 parts by mass or less of silica.   
     
     
         12 . A rubber composition, comprising:
 100 parts by mass of a rubber component including the rubber-like polymer according to  claim 1 ; and   1 part by mass or more and 100 parts by mass or less of carbon black.   
     
     
         13 . A tire tread, comprising the rubber composition according to  claim 8 .